Treating the residue resulting from manufacture of white lead.



No. 766,133. PATENTED JULY 26, 1904. J. W., F. T. & M. BAILEY. TREATINGTHE RBSIDUE RESULTING FROM MANUFACTURE 01? WHITE LEAD.

APPLICATION FILED 0012.18, 1900.

N0 MODEL.

UNITED STATES Patented July 26, 1904.

PATENT OFFICE.

JOHN WV. BAILEY, FRANK T. BAILEY, AND ARK BAILEY, OF JERSEY CITY, NETVJERSEY, ASSIGNORS, BY MESNE ASSIGNMENTS, TO UNITED LEAD COMPANY, ACORPORATION OF NETV JERSEY.

TREATING THE RESIDUE RESULTING FROM MANUFACTURE OF WHITE LEAD.

SPECIFICATION forming part of Letters Patent No. 766,133, dated July 26,1904.

Application filed October 18, 1900. Serial No. 33,423. (No specimens.)

Our invention consists in a method of treat.

ment of the waste products of lead, such as are formed in themanufacture of white lead by the corroding process.

The object of the invention is to convert these waste products intovaluable by-products instead of converting them back into metallic lead,as is usually done at great cost of time and money.

In the old Dutch process of corrosion the uncorroded parts of thebuckles are composed in the most part of metallic lead amounting inquantity to about thirty or forty per cent. of the amount of leadoriginally treated. These uncorroded parts not being in a comminutedcondition are not valuable for further treatment other than for furthercorrosion or remelting into pig-lead or new buckles.

In the more modern processes of quick corrosion, in which the lead whentreated in the corroding process is in the form of fiber or some otherfinely-comminuted condition, the residue left from washing the corrodedstock is by no means as great as it is in the old Dutch process; but itis nevertheless an important fraction of the stock under treatment.

The waste products resulting from the corrosion of lead by eitherprocess consist of a mixture of lead carbonate, lead oxid, lead acetate,and fine metallic particles.

Our invention consists first in the process of treating these wasteproducts, which consists in alternately moistening the particles formingthe said products with acetic acid and exposing them to suitablecorroding-gases, as the oxygen and carbonic acid of the air, and at thesame time causing the particles to move upon themselves, so as to causean attrition of sand particles, as a result of wluch the lead oxid andthe metallic lead in these waste prod-- nets are converted almostentirelyinto asolution of acetate of lead, the carbonate being left in apure condition, and then separating the acetate solution from thecarbonate. In the best form of our process the solution of acetate oflead is continually drawn off at one point and the carbonate of lead iscontinually removed at another point, the process being thus made anuninterrupted or self-acting one.

Our invention also consists in the process of treating these wasteproducts, which are composed mainly of carbonate of lead, oxid of lead,and metallic lead, which process consists in revolving the mass of wasteproducts so as to produce attrition of the particles, causing theparticles at one part of their revolution to pass through a solution ofacetic acid and at another part of their revolution to be exposed to theair, whereby the metallic portion of the products are converted intosoluble acetate of lead, and then separating the acetate solution fromthe carbonate. In the best form of the process the waste products arecaused to alternately pass through the body of acetic acid at the lowerpart of their revolution and to be exposed to the air at the upper partof their revolution, and the dissolved acetate of lead is caused tocontinuously flow off from the lower part of the mass when it reaches apredetermined level, and the carbonate of lead is' continuously removedfrom the top of the mass, and fresh quantities of the waste products andof the acetic acid are continuously supplied as may be needed. Ourprocess also consists in certain other features and steps hereinafterdescribed and claimed.

In the accompanying drawing is shown an apparatus which is speciallyadapted for carrying out our improved process.

In this drawing, A is an inclined cylinder open or partly open at theupper end and supported on the shaft B, which is adapted torevolve inthe inclined boxes C C.

D is a feed-pipe extending from the bottom of the hopper E to a pointnear the bottom of the cylinder. Inside of the tube D is a screw M,adapted to be revolved by any suitable means.

F'is a pipe opening into the hopper E and provided with any suitableform of. regulatingvalve. This pipe is adapted to continuously supplythe acetic acid from anysuitable source. The lower part of the cylinderis provided with openings or outlets L L, as shown, for the purpose ofallowing the solution of acetate of lead to escape when it reaches acertain level in the cylinder. G is any suitable receptacle in whichthis acetate of lead can be collected.

The Waste products are put in the hopper E and are continuously fed intothe cylinder A through the pipe D by means of the revolving screw M.Acetic acid is supplied to the hopperE through the pipe F insuitably-regulated quantities and is thoroughly mixed with the Wasteproducts while passing through the pipe D by means of the screw M. WVeprefer to employ a solution of acetic acid and water of a strengthsufficient to dissolve the oxid of lead and the metallic lead, but notto dissolve carbonate of lead to a material extent. A suitable strengthof solution would consist of twelve and one-half per cent. of twenty-sixper cent. acid. The waste products are supplied to the hopper E insuflicient quantities to fill the cylinder up to the level indicated atH and to keep the cylinder full to this level. A suflicient quantity ofacetic acid is fed in to keep the acid which collects in the bottom ofthe cylinder up to the level indicated atKthat is to say, up to thelevel of the outletL when at the lowest point in its revolution. As theproducts are fed into the cylinder every particle is wet or moist withthe acetic-acid solution. In the upper part of the cylinder above theline K the particles are subjected to the oxidizing action of the airand the acid solution, every particle of waste products meanwhile beingin constant motion, producing an attrition of the particles. Themetallic portion is rapidly converted into soluble oxids of lead. Theoxids and a very small portion of the carbonate are also dissolved bythe acetic acid. This solution runs off through the outlets L when theyare in the lowest part of their revolution and into the vessel G. As themass continues to revolve the particles of lead and oxid which have notpreviously been converted into soluble acetate of lead are again wet ormoistened by acetic acid in the bottom of the cylinder and are againexposed to the air in the upper part of the cylinder and are therebyconverted into soluble acetate and are dissolved and flow off into thevessel G upon the further revolution of the cylinder. The tubes oroutlets L L are preferably covered with a line brass or othernon-corrodible screen to prevent solid particles escaping into thevessel G. The undissolved and unmixed carbonate of lead being lighterthan-the other substances in the cylinder and being continuouslydisplaced by the fresh quantities deposited in the lower end of thecylinder collects at the upper end thereof and is continuouslydischarged therefrom, as at H, in the manner illustrated, and thenwashed to free it from the remnants of acid, is dried, and is then apure white lead of commercial value.

. As already explained, the oxids and metallic particles escape asdissolved acetate of lead into the receptacle G. The solution fedthrough the pipe F can be so regulated as to produce a discharge intothe passage Gr of a richness in acetate of lead from seventeen totwenty-two per cent. This solution, which is rich in lead, is thentreated in the usual manner for converting the lead into commercialacetate of lead, .or by using suitable precipitants into chromates,chlorids, sulfates, &c., or into flake white, which is simplyprecipitated carbonate of lead.

The apparatus herein shown and described is not claimed herein, the sameforming the subject-matter of another application, Serial No. 33,425,filed simultaneously herewith.

What we claim as new, and desire to secure by Letters Patent, is'

1. The process of treating the waste products of'lead such as are formedin the manufacture of white lead by the corrodingprocess,

said waste products being composed mainly of carbonate of lead. oxid oflead and metallic lead, which consists in alternately moistening thesaid products with acetic acid and exposing them to suitablecorroding-gases and at the same time causing the particles of which theproducts are composed to move upon themselves, whereby the metallic leadin the waste products is converted almostentirely into a solution ofacetate of lead, then separating the acetate solution from thecarbonate, substantially as set forth.

2. The process of treating the waste products of lead which are formedin the manufacture of white lead, and which are composed mainly ofcarbonate of lead, oxid of lead, and metallic lead, which processconsists in moistening the particles forming the mixture with aceticacid of such strength that it will attack the oxid of lead and themetallic lead but not the carbonate, exposing the particles to the air,whereby some of the oxid of lead and of the metallic lead are convertedinto soluble acetate of lead, causing the particles to move uponthemselves so as to produce attrition thereof, then treating theparticles again with acetic acid, and then exposing them again to theair, meanwhile causing the particles to move upon themselves, wherebymore of the oxid of lead and of the metallic lead are converted intosoluble acetate of lead, and continuing this treatment untilsubstantially all of the oxid and the metallic lead have been soconverted, and then separating the solution of acetate of lead from thecarbonate of lead, substantially as set forth.

3. The process of treating the waste products of lead which are formedin the manufacture of white lead, and which are composed mainly ofcarbonate of lead, oxid of lead, and metallic lead, which processconsists in revolving the mass of waste products so as to produceattrition of the particles, causing them at one part of their revolutionto pass through a body of acetic-acid solution, and at another part oftheir revolution to be exposed to the air, whereby the lead oxid and themetallic lead in the products are converted into soluble acetate of leadand separating the acetate solution from the carbonate, substantially asset forth.

a. The process of treating the waste products of lead which are formedin the manufacture of white lead, and which are composed mainly ofcarbonate of lead, oxid of lead,'and metallic lead, which consists inrevolving the mass of waste products so as to produce attrition of theparticles, causing them at the lower part of their revolution to passthrough a body of acetic acid, and at the upper part of their revolutionto be exposed to the air whereby the lead oxid and the metallic leadinthe products are converted into soluble acetate of lead, causing thedissolved acetate of lead to flow off from the lower part of the masswhen it reaches a predetermined level, and removing the carbonate oflead from the top of the mass, and supplying fresh quantities of aceticacid as required, substantially as set forth.

5. The process of treating the waste prod ucts of lead which are formedin the manufacture of white lead, and which are composed mainly ofcarbonate of lead, oxid of lead, and metallic lead, which consists infeeding the waste products into a revolving vessel, maintaining a supplyof acetic acid in the lower part of the vessel at a given level so thatthe products will come into contact with the acid, exposing the productsto the action of the air at the upper part of the vessel, causing thedissolved acetate of lead to flow off from the vessel at the said leveland causing the carbonate of lead to be automaticallydischarged from thetop of the vessel, substantially as set forth.

6. The process of treating the waste products of lead which are formedin the manufacture of white lead, and which are composed mainly ofcarbonate of lead, oxid of lead, and metallic lead, which consists infeeding the waste products and a regulated quantity of acetic acid intoa revolving vessel, maintaining a supply of acetic acid in the lowerpartof the vessel at a given level so that the products will come intocontact with the acid, exposing the products to the action of the air atthe upper part of the vessel, causing the dissolved acetate of lead toflow off from the vessel at the said level and causing the carbonate oflead to be automatically discharged from the top of the vessel,substantially as set forth.

7. The process of treating the waste products resulting from themanufacture of white lead by the corroding process, said waste productsbeing composed mainly of carbonate of lead, oxid of lead and metalliclead, which process consists in alternately subjecting the products tothe action of acetic acid and a suitable corroding-gas.

8. The process of treating the waste products resulting from themanufacture of white lead by the corroding process, said waste productsbeing composed mainly of carbonate of lead, oxid of lead and metalliclead, which process consists in alternately subjecting the products tothe action of acetic acid and air.

9. The process of treating the waste products resulting from themanufacture of white lead by the corroding process, said waste productsbeing composed mainly of carbonate of lead, oxid of lead and metalliclead, which process consists in alternately subjecting the products tothe action of acetic acid and a suitable corroding-gas, and causing theparticles of which the products are composed to move upon themselves.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

JOHN W'. BAILEY. FRANK T. BAILEY. MARK BAILEY. \Vitnesses:

JOHN O. GEMPLER, EDWIN SEGER.

